Can a doctor lie to you about terminal illness?

I had a diagnosis of cardiomyopathy as the result of a stress test. I had a cardiac MRI done a few months later. When I met with the cardiologist he started the appointment with the question: If you were dying, would you want to know?

I thought it over and told him that I wasn't sure, but probably not.

He then told me that nothing was seriously wrong other than some sinus tachycardia. 

I have since been having a lot of PVCs and have been told by the same doctor that it is just stress but I can't get that first appointment out of my head.

I still think that there would be benefits to not knowing but, if I were dying, I think I'd want to pursue a few things before I go that I probably wouldn't otherwise. I certainly would change some things about my life and make some preparations. 

Could he be lying to me?

Is that something they are allowed to do?